From 1e467d22eab4738daf5e90f855f98e898c52a8c2 Mon Sep 17 00:00:00 2001
From: Ted Cassirer <ted.cassirer1@ocado.com>
Date: Tue, 9 Jan 2024 17:46:09 +0700
Subject: [PATCH] Day 18

---
 aoc_cas/aoc2023/day18.py   | 58 ++++++++++++++++++++++++++++++++++++++
 tests/fixtures/2023/18.txt | 16 +++++++++++
 2 files changed, 74 insertions(+)
 create mode 100644 aoc_cas/aoc2023/day18.py
 create mode 100644 tests/fixtures/2023/18.txt

diff --git a/aoc_cas/aoc2023/day18.py b/aoc_cas/aoc2023/day18.py
new file mode 100644
index 0000000..2ecc99a
--- /dev/null
+++ b/aoc_cas/aoc2023/day18.py
@@ -0,0 +1,58 @@
+from aoc_cas.common import Coordinate, DIR_RIGHT, DIR_DOWN, DIR_UP, DIR_LEFT, Direction
+
+directions: dict[str, Direction] = {
+    "U": DIR_UP,
+    "D": DIR_DOWN,
+    "R": DIR_RIGHT,
+    "L": DIR_LEFT,
+}
+directions_hexa = [
+    DIR_RIGHT,
+    DIR_DOWN,
+    DIR_LEFT,
+    DIR_UP,
+]
+
+
+def parse_dig_coords(data: str, use_encoded: bool = False) -> tuple[list[Coordinate], int]:
+    coords: list[Coordinate] = [Coordinate.create(0, 0)]
+    total_distance = 0
+    for line in data.splitlines():
+        direction, k, encoded = line.split(" ")
+        if use_encoded:
+            distance_str = encoded[2:7]
+            dir_str = encoded[7]
+            dir = directions_hexa[int(dir_str, 16)]
+            distance = int(distance_str, 16)
+        else:
+            dir = directions[direction]
+            distance = int(k)
+        coords.append((coords[-1].move(dir, distance)))
+        total_distance += distance - 1
+        # for _ in range(int(distance)):
+        #     coords.append(coords[-1].move(dir))
+    return coords[:-1], total_distance - 1
+
+
+def calculate_area(coords: list[Coordinate]) -> int:
+    shifted = coords[1:] + [coords[0]]
+    s1 = sum((c1.y + c2.y) * (c1.x - c2.x) for c1, c2 in zip(coords, shifted))
+    return s1 // 2 + len(coords) // 2 + 1
+
+
+def part_a(data: str) -> int:
+    dig_coords, length = parse_dig_coords(data)
+    area = calculate_area(dig_coords)
+    return area + length // 2 + 1
+
+
+def part_b(data: str) -> int:
+    dig_coords, length = parse_dig_coords(data, use_encoded=True)
+    area = calculate_area(dig_coords)
+    return area + length // 2 + 1
+
+
+if __name__ == "__main__":
+    from aoc_cas.util import solve_with_examples
+
+    solve_with_examples(year=2023, day=18)
diff --git a/tests/fixtures/2023/18.txt b/tests/fixtures/2023/18.txt
new file mode 100644
index 0000000..e22a810
--- /dev/null
+++ b/tests/fixtures/2023/18.txt
@@ -0,0 +1,16 @@
+R 6 (#70c710)
+D 5 (#0dc571)
+L 2 (#5713f0)
+D 2 (#d2c081)
+R 2 (#59c680)
+D 2 (#411b91)
+L 5 (#8ceee2)
+U 2 (#caa173)
+L 1 (#1b58a2)
+U 2 (#caa171)
+R 2 (#7807d2)
+U 3 (#a77fa3)
+L 2 (#015232)
+U 2 (#7a21e3)
+62
+952408144115
\ No newline at end of file